What is Folliculitis?
Folliculitis is inflammation of the hair follicles in the skin. In most cases it is caused by bacterial infection. It often presents as small, red or pus-filled lumps at the base of hairs which can sometimes be itchy. It is a common condition and, in mild cases, symptoms usually clear up on their own.
Initially folliculitis may appear as small lumps appear in a grid-like pattern on the skin. The most commonly affected areas of skin include the: armpits, beard, face, scalp, thighs and groin area. Folliculitis can also affect the eyelashes, causing a stye.
It can sometime become more severe and cause widespread redness (erythema) and lead to scarring (including keloid scars) and hair loss. The infection may spread to surrounding skin where it can form a larger pus-filled lump known as a boil or furuncle. Groups of furuncles may join together to form an even larger pus-filled lump known as a carbuncle. Furuncles and carbuncles are signs of a more deep-seated infection of the skin.
Topical antibiotics, topical antiseptics and oral antibiotics are used to treat more severe or recurrent episodes of folliculitis.
While there are a variety of causes the majority of cases of folliculitis are caused by infection of the hair follicle by a bacterium known as Staphylococcus aureus. Hair follicles that are damaged (for example by friction or shaving) or blocked are more susceptible to infection with this bacteria.
There are a number of risk factors including having a bears, shaving against the grain, having thick curly hair and excessive sweating. Avoiding tight fitting clothes may help.
The main symptom of folliculitis is small red or pus-filled lumps on hairy areas of skin. Folliculitis cannot occur on hairless areas of skin, such as the palms or soles of the feet. Sometimes these small lumps appear in a grid-like pattern on the skin. The most commonly affected areas of skin include the: armpits, beard, face, scalp, thighs and groin area. Folliculitis can also affect the eyelashes, causing a stye.
Folliculitis often starts off as a rash with lumps slowly developing over time. The rash may or may not be itchy. In mild cases, the rash resolves on its own. Folliculitis that is more severe can cause widespread redness (erythema) and lead to scarring (including keloid scars) and hair loss.
The infection of the hair follicle in folliculitis may spread to surrounding skin. When this happens, it can form a larger pus-filled lump known as a boil or furuncle. Groups of furuncles may join together to form an even larger pus-filled lump known as a carbuncle. Furuncles and carbuncles are signs of a more deep-seated infection of the skin.
Types of folliculitis
There are different types of folliculitis, which vary in cause.
- Sycocis barbae – this is chronic folliculitis that affects the beard area in men. The skin can be particularly itchy and painful, especially on shaving. The upper lip can also be affected.
- Hot tub folliculitis – hot tubs with warm water encourage the growth of bacteria, particularly an organism called Pseudomonas spp. People who frequently use hot tubs may develop this form of folliculitis.
- Gram-negative folliculitis – a class of bacteria known as Gram-negative bacteria can less commonly infect hair follicles. This type of folliculitis is more likely to happen after long-term treatment for acne using antibiotics.
- Pseudo-folliculitis – this is where small bumps form due to ingrowing hairs. The bumps are not due to pus or infection and thus it is not a true form of folliculitis. Ingrowing hairs are more common in people with curly hair, as hairs are more likely to curl inwards and re-penetrate the skin. This causes small red bumps.
The majority of cases of folliculitis are caused by infection of the hair follicle by a bacterium known as Staphylococcus aureus. Hair follicles that are damaged (for example by friction or shaving) or blocked are more susceptible to infection with this bacteria. The infection causes inflammation and the formation of pus – leading to small pus-filled lumps. Some people may carry Staphylococcus aureus bacteria in their nose, where it is usually harmless.
Folliculitis may also be caused by other organisms.
In hot tub folliculitis, regular exposure of the skin to moist, warm conditions can cause another bacterium, Pseudomonas spp, to infect the hair follicles.
In Gram-negative folliculitis, other bacteria such as Klebsiella and Enterobacter spp cause infection of hair follicles. These organisms are more likely to cause folliculitis after long term antibiotic treatment for acne.
Fungal infections can also cause folliculitis. In men, a condition known as tinea barbae results from fungal infection of the hair follicles in the beard area and around the lips. As well as pustules, the condition causes crusting of the skin.
Herpetic folliculitis is inflammation of the hair follicle caused by the herpes simplex virus. This is the same virus that is responsible for cold sores. Consequently the infected hair follicles may be near to cold sores on the face.
There are also rare autoimmune disorders that can give rise to folliculitis.
Blocked or damaged hair follicles are more likely to become infected and develop folliculitis. Factors that increase the risk of blocked or damaged hair follicles include:
- having thick and curly hair
- having an uncut beard
- shaving against the grain
- friction from tight clothing
- wounds and abrasions to the skin
- excessive sweating and hyperhidrosis
- skin that has been occluded by other medication
People with weakened immune systems are also more likely to develop folliculitis.
A doctor can normally diagnose folliculitis from a simple examination of the skin. Further investigations are rarely required.
If folliculitis is recurrent, then skin scrapings, biopsies and swabs to test whether you are carrying the Staphylococcus aureus bacteria may be required.
Most cases of folliculitis are mild and resolve on their own without treatment. Usually this takes between 7 and 10 days. It is also helpful to make certain lifestyle adjustments (See Lifestyle Advice).
Emollients (moisturisers) containing antibacterial agents can help to destroy bacteria and soothe the skin. They are suitable for mild cases of folliculitis and available to buy over the counter.
Infections that are more severe may require treatment with antibiotic creams. These are applied to the skin 3-4 times a day until the folliculitis has settled. Fucidin cream is often the first-line topical antibiotic for treating folliculitis. They work by destroying the bacteria inside the hair follicles.
Antiseptic lotions and solutions, such as chlorhexidine, iodine or triclosan, are sometimes used to disinfect the skin and hair follicles.
For more deep-seated and severe widespread infections, oral antibiotics may be needed over a period of 4-6 weeks.
Topical antifungal creams
For folliculitis caused by fungal infections, a topical antifungal cream such as clotrimazole of ketoconazole may be required. Oral antifungal tablets are sometimes prescribed instead.
Antiviral drugs such as aciclovir are used to treat folliculitis caused by the herpes simplex virus (herpetic folliculitis).
In the event that folliculitis causes boils and carbuncles to develop, surgical drainage may be required. This usually performed by making a small cut into the boil and draining away the pus.
For mild cases of folliculitis, certain things may help and speed up recovery. These include:
- Consider shaving less frequently – this will allow the folliculitis to settle down without the reintroduction of bacteria to the hair follicle. It can also help prevent further damage or blockage.
- Shave with the grain/ in the same direction as hair grows – shaving with the direction of hair (rather than against it) reduces the risk of damage to hair follicles.
- clean shaving equipment thoroughly with surgical spirit – this destroys bacteria and lowers the risk of infection.
- Avoid tight fitting clothes – tight fitting clothes can increase skin moisture and increases the chance of follicles becoming blocked and infected.
- Avoid sharing towels and bed linen – this prevents the infection from passing to other people. Regularly washing these items is also recommended.
Bernard, P. (2008). Management of common bacterial infections of the skin. Current opinion in infectious diseases, 21(2), 122-128.
Folliculitis. Patient.info (2014). Available online at: http://patient.info/health/folliculitis-leaflet
Folliculitis. Professional Reference article. Patient.info (2013). Avaialble online at: http://patient.info/doctor/folliculitis-pro